South Korean battery maker Samsung SDI and US auto giant General Motors will build a joint battery manufacturing plant for electric vehicles in the US with an investment worth up to 5 trillion won ($3.8 billion), according to reports Sunday.

The battery alliance, which will mark the first collaboration between the two companies, will become official later this week as they are expected to sign a memorandum of understanding in Michigan on Wednesday.

Citing unnamed industry sources, the reports said the two sides are undergoing last-minute negotiations for details in the agreement such as the production volume of the joint EV battery factory, the investment method and the location of the plant. The companies are projected to break ground for the joint factory at the end of this year and the plant is expected to start producing prismatic and cylindrical battery cells in 2026.

The capacity of the joint plant is estimated between 30 to 50 gigawatt-hours per year. The annual capacity of 50 GWh is enough to produce 600,000 or more EVs annually.

Regarding the reports on the joint project with GM, a Samsung SDI official told The Korea Herald that the company could not provide any comment on matters related to its customers.

When LG Energy Solution and GM reportedly halted their plan to build a fourth EV battery plant in the US in January, automotive and battery industry insiders already pointed to Samsung SDI as the alternative option for the US automaker.

The GM partnership is Samsung SDI’s second joint project in North America after the Korean battery maker announced the plan to build a $2.5 billion battery plant in Indiana with Stellantis last May. The Indiana factory is expected to begin operation in the first quarter of 2025 with an annual production capacity of 23 GWh.

The latest partnership shows the trend of the battery industry expanding its customer pool instead of sticking with just one automaker and global carmakers looking to secure stable battery supplies as they dial up their EV production to cope with the US Inflation Reduction Act that provides $7,500 subsidies per EV.

LG Energy Solution, Korea’s leading battery maker by sales volume, has joined hands with GM, Stellantis, Honda, Hyundai Motor Group and Ford while Samsung SDI now has partnerships with Stellantis and GM. Another Korean battery maker SK On is collaborating with Ford and Hyundai Motor Group.